The present disclosure relates to a device which allows to obtain at least a double visual validation security mark, that is, revealed when held against the light, and by the incidence or application of a means to temporarily reveal the security mark, as for example, ultraviolet light, polarized light, infrared light, heat, and/or other revealing means. Said security mark is applicable on the most varied layered substrates such as cotton-, flax-, cellulose-produced paper, a combination of the above or of any other type. This type of device may be used for an industrial application according to the method disclosed in this same document in order to produce the security marks that are applicable and which are difficult to reproduce by an unauthorized person so that they serve as a security measure against counterfeiting, allowing a person to authenticate the origin of the paper received. A clear object of incorporating this type of security marks is to prevent counterfeiting of certificates, official documents, documents of value, e.g., banknotes, postage stamps, passports, tickets, bonds, certificates, and the like. In response to the continuing evolution of developments in this field of art, bellow there is a brief overview or reference framework that is considered relevant to demonstrate the advantages obtained by the present invention.
Among the many and ever-increasing security measures designed to prevent counterfeiting of certificates, official documents, passports, tickets, banknotes, documents of value, and the like, it is well known the continuing, widespread and reliable use of the so-called watermarks. Said watermarks are basically an image formed by a subtle difference of thicknesses and/or densities in a sheet of paper obtained during paper manufacturing process, more specifically when the paper pulp that is still wet is pressed against a roller having a relief or depression with the image to be incorporated on the paper as a watermark.
A watermark becomes visible when said type of paper is held to the light. It is noteworthy that for the purposes of the present invention when referring to paper, a person skilled in the art understands that this is for the purposes of descriptive clarity and simplicity, and said term “paper(s)” shall include herein any type of layered substrate, such as any sheet of paper, which for practical purposes, and in order to obtain a high mechanical strength, is obtained with cotton or flax fibers, or combinations thereof. At present, the main interest of using said watermark is to demonstrate the authenticity of the paper or print origin. Basically, a watermark, when applied to documents and certificates of value, especially when applied to documents of value, such as those mentioned above and equivalent embodiments, it prevents obtaining counterfeited documents by photocopying, scanning and printing them. This makes it a durable, easy to verify and hard to counterfeit security feature, which may contain an image such as a very simple drawing, sign, symbol or otherwise incorporate a highly detailed image displaying multiple tones when viewed against the light.
When this security technology is applied to documents of value, the image displayed by the watermark usually varies according to the type of paper document in which it will be applied, whether a certificate, banknote, bond, etc. Usually, the watermark image is related to the rest of the figures, decorations, symbols and images that are obvious on casual inspection.
While this particular and mutual relationship between the image of the visible printing of the document of value and the watermark image (only visible when held to the light) represents a very efficient security feature against counterfeiting, from the practical point of view during the manufacture of said certificates, official documents, documents of value such as bonds, passports, tickets, banknotes and the like, their use requires special care since each sheet of paper must be properly combined with the watermark which comes from the manufacturer with the subsequent permanent and usually two-sided printing visible with traditional ink, to match each watermark image with the correct traditional visible printing.
A person skilled in the art, for example, engaged in manufacturing documents of value and/or the like, knows that they not always have enough sheets of paper with a particular watermark design for a production batch, and at the same time they can have an idle number of sheets of paper with another watermark design that is not in use for some time, or even that has become obsolete.
In response to said problem, the inventor of the present invention has proposed in the past a method to produce a sheet of paper with a positionable security stamp. Said positionable stamp can be seen in U.S. Pat. No. DE 3,718,452 of this same inventor, wherein it has been proposed to obtain an optical effect similar to that of a watermark, but with the advantage that the stamp can be produced in a sheet of paper already manufactured and therefore avoiding the logistics and storage limitations mentioned above. Therefore, said proposal offers a significant advantage over its background since it allows to incorporate security marks which can be seen when held to the light through a new method applicable in the press itself which then will continue with the rest of the visible printing of the document of value. Thus, the press itself is capable of providing as many authenticated sheets of paper with this special marking as needed, wherein said marked sheets of paper then comprise the specific security stamp of each document of value, document and/or the like.
In short, the method proposed in said disclosure, is performed based on the use of a mold with projections in relief corresponding to a previously engraved design or drawing in said mold; the engraving mold is mounted on a carrier so as to be able to put the sheet of paper on the mold such that thus mounted the sheet of paper is subjected to the pressure of a roller and thus causing the deformation of the sheet of paper with recesses and projections similar to those of the die where it rests. Eventually, was proposed to reduce the thickness of the ridges of the paper by means of a rotary grinding wheel, which partly wears out paper thickness. Said proposal can be seen in the disclosure of said U.S. Pat. No. DE 3,718,452, which is herein incorporated by reference in its entirety. However, the invention continues obtaining as a result a mere emulation of a watermark only visible when held to the light, which can even coexist with other preexisting watermarks, but which does not add any further feature for authentication of documents of value.
Further developments of the same inventor of the present invention, take into account the need to solve some problems such as avoiding paper shifting when the paper is rolled in the stamping cylinder, as well as preventing the formation of undesirable creases in the paper and the consequent paper breakage, among other things which are reflected in U.S. Pat. No. 6,110,022, of the same inventor; wherein and all which is therein disclosed is herein incorporated by reference in its entirety. In said disclosure the inventor focuses on incorporating paper adjustment means on the surface of the peripheral wall of the support cylinder comprised in a pneumatic circuit and arranged adjacent to the area between the support cylinder and the grinding wheel; and on incorporating brushes (acting as paper-pressing means) projecting against the peripheral wall of the cylinder. Thus, the invention proposes an obvious improvement of the method for fixing the paper on the roll; however, the type of security mark obtained remains the same type known in the prior U.S. Pat. No. DE 3,718,452, not bringing substantial improvements on the antifraud qualities of the security marks obtained.
It can be seen therefore that successive proposals have allowed to avoid the need to purchase the specially marked sheet of paper from the manufacturer capable of incorporate a watermark at the time of production of the same from the pulp, but they have not provided any advances regarding devices and methods directed to obtain more complex security features in order to obtaining a more secure authentication. It is understandable, therefore, the continuing need for new devices and methods for obtaining new types of security marks applicable to documents of value, and the like. Security marks increasingly demand high standards of antifraud security and the capacity of coexisting with other preexisting security measures or being subsequently inserted into the sheet of paper, among which there are holographic bands, fluorescent fibers, transparent windows, and even watermarks. A person skilled in the art knows that incorporating new antifraud security elements in a document of value and/or the like, is not an easy task considering that each security element incorporated must be able to be applied with absolute precision on the sheet of paper (substrate), be compatible with other security elements already present and stand the test of time by the constant manipulation and without adding significant costs.
Based on the above, and as will be shown in detail below in the section directed to the detailed description, the present invention has offered significant advantages over all the prior art known, since it proposes a new device for producing a suitable security mark for obtaining a new and accurate abrasive gravure printing of a pre-designed image on the front (obverse) of the substrate and a simultaneous printing of the same pre-designed image on the back (reverse) of the same substrate.
While for purposes of clarity the invention will be better described with reference to a sheet of paper and obtaining documents of value, the description, when made in singular regarding each element extends also to the description in plural of a plurality of said elements and the particular description referred to a document of value is equivalent and can be applied to certificates, official documents, passports, banknotes, tickets, bonds, and the like without any limitation, formed on a sheet of paper with the extent of the definition given above.